The present invention relates to a method of and an apparatus for manufacturing plural types of glass molding articles.
In recent years, studies and research have been conducted on a method of manufacturing glass molding articles, in which a plurality of molds, each of which has had its surfaces formed respectively into optical mirror surfaces and each of which is made of a special or distinctive material, are used to press-mold glass materials within a non-oxidizing atmosphere, thereby producing the glass molding articles such as lenses or the like having optical mirror surfaces, which do not require further processings such as grinding finishing or the like after the press-molding. Applicant of this invention has already proposed an apparatus for carrying out the above-described method in Japanese Patent Laid-Open No. HEI 1-157425.
The apparatus according to the proposed invention comprises a plurality of processing compartments including a takeout/insertion compartment, a heating compartment, a soaking compartment, a press compartment, a cooling compartment and so on. These compartments have their respective processing functions which are different in nature or operation from each other. The processing compartments are arranged along a circle in order of processing steps. A plurality of molds having glass materials to be molded therein are connected in series to each other. In operation, the molds remain at the processing compartments for a predetermined period of time and, thereafter, are successively moved to their respective subsequent processing compartments by means of a mold moving mechanism which is in the form of a rotary table. In this manner, a series of precision molding steps can be done continuously.
In recent years, phenomena have advanced such as diversification of a use, shortening of life cycle of products, etc. in the field of manufacturing glass molding articles. Attendant upon the advance, an urgent need is present in the industry to be able to produce various types of molded glass articles in small batches, while simultaneously reducing production and delivery time. For example, in the case where plural types of optical components are combined with each other to form one set and a plurality of sets are needed simultaneously for delivery, it is impossible to deliver the sets until all of the optical components have been manufactured.
The manufacturing apparatus for the glass molding articles described previously is effective in the case where a single kind of glass molding article is manufactured. However, the molding apparatus is not necessarily suited for the case where plural types of glass molding articles are manufactured.
That is, if a variety of glass molding articles are to be produced by the use of a single manufacturing apparatus, it is necessary to keep the various processing chambers running at optimum conditions while manufacturing the respective glass molding articles, in the single molding apparatus. In short, heating temperature, soaking temperature, press temperature, gradual-cooling temperature, press time, press pressure and so on, that are the processing steps of the glass molding articles, all differ if the glass molding articles differ. Normally, glass molding articles must be produced in accordance with smooth temperature schedule in the following manner. That is, a glass material to be molded, which is inserted in the apparatus, is gradually heated within a predetermined compartment. At a particular point in time, the temperature of the glass material reaches a predetermined level, and the glass material is pressed. Subsequently, the glass material is gradually cooled to produce the glass article. Accordingly, in order to simultaneously mold a variety of glass materials within the same apparatus in a known manner in mixture, a known plurality of compartments must exist in mixture which are different in processing condition from each other so as to adequately treat every glass material to be molded. At this time, the series of compartments vary in temperature and an extremely strange or unique condition is present. Thus, in the past, no notice has been made of the fact that plural types of glass materials can be simultaneously molded within a single apparatus.
As described above, if an attempt is made to manufacture a variety of glass molding articles by means of the apparatus mentioned above within a short period of time, it would be necessary to install or mount a multiplicity of apparatuses in accordance with the types of the glass articles to be molded. Since, however, the apparatus of the type referred to above is extremely expensive, the stupendous cost of equipment would be inhibiting to potential manufacturers. In addition, the apparatus has a productive capacity more than is necessary with respect to the single type of glass to be molded, thereby resulting in reduction of the rate of operation.